Cheese quality from cows given a tannin extract in 2 different grazing seasons.

The aim of the present study was to compare the effect of dietary tannins on cow cheese quality in 2 different grazing seasons in the Mediterranean. Two experiments were performed on 14 dairy cows reared in an extensive system. The first experiment took place in the wet season (WS), and the second experiment took place in the dry season (DS). In the WS and DS experiments, cows freely grazed green pasture or dry stubbles, respectively, and the diet was supplemented with pelleted concentrate and hay. In both experiments, the cows were divided into 2 balanced groups: a control group and a group (TAN) receiving 150 g of tannin extract/head per day. After 23 d of dietary treatment, individual milk was collected, processed into individual cheeses, and aged 25 d. Milk was analyzed for chemical composition, color parameters, and cheesemaking aptitude (laboratory cheese yield and milk coagulation properties). Cheese was analyzed for chemical composition, proteolysis, color parameters, rheological parameters, fatty acid profile, and odor-active volatile compounds. Data from the WS and DS experiments were statistically analyzed separately with an analysis of covariance model. In the WS experiment, dietary tannin supplementation had no effect on milk and cheese parameters except for a reduced concentration of 2-heptanone in cheese. In the DS experiment, TAN milk showed lower urea N, and TAN cheese had lower C18:1 trans-10 concentration and n-6:n-3 polyunsaturated fatty acid ratio compared with the control group. These differences are likely due to the effect of tannins on rumen N metabolism and fatty acid biohydrogenation. Dietary tannins may differently affect the quality of cheese from Mediterranean grazing cows according to the grazing season. Indeed, tannin bioactivity on rumen metabolism seems to be enhanced during the dry season, when diet is low in protein and rich in acid detergent fiber and lignin. The supplementation dose used in this study (1% of estimated dry matter intake) had no detrimental effects on cheese yield or cheesemaking parameters. Also, it is unlikely that sensorial characteristics would be affected by this kind of dietary tannin supplementation.

Plant secondary compounds as complementary resources: are they always complementary?

Generalist herbivores typically grow better on mixed- than on single-component diets. This response has been attributed to food complementarities that either enhance the utilization of nutrients or dilute the negative impacts of plant secondary compounds (PSC). For instance, when animals choose between foods that contain diverse PSC, they eat more than animals offered a food that contains just one PSC. In addition to their negative impacts on herbivore fitness, recent evidence suggests that at appropriate doses PSC may provide beneficial effects to herbivores (i.e., by reducing parasitic infections). Thus, complementarities among diverse PSC may not only influence an herbivore's ability to consume food but also reduce the incidence of disease. We assessed the complementary effects of two PSC by offering sheep (Ovis aries) a choice of foods containing condensed tannins and saponins while challenged with a parasitic (Haemonchus contortus) infection. Animals offered a choice ate more than animals just offered tannins or saponins in single rations. However, sheep offered choices displayed greater fecal egg counts (an indirect measurement of parasitic burdens) than sheep offered single rations. Thus, saponin- and tannin-containing foods were complementary resources regarding nutrient intake but antagonistic regarding effects on parasitic loads. The nature of the relationship among PSC may depend on the dimension (i.e., nutrient intake, disease) where the interaction occurs. A unifying currency such as growth or reproductive output may help understand the trade-offs between costs (disease) and benefits (nutrient and medicine intake) for herbivores grazing multiple PSC.

Strategies for keeping dairy cows and calves together - a cross-sectional survey study.

Although it is still most common to rear dairy calves separately from adult cattle, the interest in prolonged contact between dairy calves and lactating cows during early life is increasing. Previous research has documented positive effects of cow-calf contact (CCC) on for example early calf growth and udder health of suckled cows, but also negative effects such as increased separation distress and reduced weight gains after weaning. The aim of this study was to use information from European farms with prolonged cow-calf contact to identify innovative solutions to common challenges for CCC farms. Commercial dairy farms that kept calves with adult lactating cows for seven days or more after birth were invited to participate, and interviews were performed with 104 farmers from six countries. During interviews, information about farm management, calf rearing, farmers' perception of animal health on their farm, and farmers' drivers and barriers for implementing CCC were collected. We found that CCC was practised in a large variety of housing and management systems, and that calves could be reared together with their dam, with foster cows, or using a combination of the two. The contact period varied considerably (7-305 days) between farms and about 25% of the farms manually milk fed the calves during parts of the milk feeding period. Daily contact time varied between farms, from 30 minutes per day to permanent contact except at milking. Behaviours indicative of separation distress, most commonly vocalisation in cows and calves, were reported by 87% of the farmers. Strategies to alleviate separation distress, for example simultaneous gradual weaning and separation, were used on some farms. Building constraints were most often mentioned as a barrier for implementing CCC. Our findings suggest that CCC is practised in a variety of commonly used husbandry systems. Reported challenges were primarily related to weaning and separation, and to building constraints; these aspects should be areas of future research.

Effect of dietary tannin supplementation on cow milk quality in two different grazing seasons.

Extensive farming systems are characterized by seasons with different diet quality along the year, as pasture availability is strictly depending on climatic conditions. A number of problems for cattle may occur in each season. Tannins are natural polyphenolic compounds that can be integrated in cows' diet to overcome these seasonal problems, but little is known about their effect on milk quality according to the season. This study was designed to assess the effects of 150 g/head × day of tannin extract supplementation on proximate composition, urea, colour, cheesemaking aptitude, antioxidant capacity, and fatty acid (FA) profile of cow milk, measured during the wet season (WS) and the dry season (DS) of Mediterranean climate. In WS, dietary tannins had marginal effect on milk quality. Conversely, in DS, the milk from cows eating tannins showed 10% lower urea and slight improvement in antioxidant capacity, measured with FRAP and TEAC assays. Also, tannin extract supplementation in DS reduced branched-chain FA concentration, C18:1 t10 to C18:1 t11 ratio and rumenic to linoleic acid ratio. Tannins effect on rumen metabolism was enhanced in the season in which green herbage was not available, probably because of the low protein content, and high acid detergent fibre and lignin contents in diet. Thus, the integration of tannin in the diet should be adapted to the season. This could have practical implications for a more conscious use of tannin-rich extracts, and other tannin sources such as agro-industrial by-products and forages.

Dietary tannins improve lamb meat colour stability.

Fourteen male Comisana lambs were divided into two groups at 45days of age: lambs fed a concentrate diet (C), or lambs fed the same concentrate with the addition of quebracho (Schinopsis lorentzii) tannins (T). Sheep were slaughtered at 105days of age. Lipid oxidation, colour coordinates, haem pigment concentration, and metmyoglobin percentages were measured on minced semimembranosus muscle (SM) over 14days of refrigerated storage in a high oxygen modified atmosphere. Tannin supplementation increased (P<0.01) a(∗) values and reduced (P<0.01) b(∗) values of the SM when compared to C. Lower hue angles (P<0.001) and metmyoglobin formation (P=0.07) were observed in lamb from T-fed compared to C-fed sheep during the 14-days storage period. Furthermore, feeding T resulted in greater (P<0.001) haem pigment concentrations in the SM during refrigerated storage; however, diet had no (P=0.28) effect on lipid oxidation. Therefore, including quebracho tannins in sheep diets can improve meat colour stability of fresh lamb during extended refrigerated storage.

Lipid and colour stability of meat from lambs fed fresh herbage or concentrate.

Fourteen male Comisana lambs were divided into two groups at 45days of age and were individually penned for 105days. Over this period, seven lambs were fed a concentrate-based diet (C), whereas the remaining animals received vetch (Vicia sativa; H) harvested daily and given fresh to the animals. Lipid oxidation was measured in both minced cooked meat (semimembranosus muscle, SM) over 4days of aerobic refrigerated storage and on minced raw meat stored over 14days in a high oxygen atmosphere. Colour descriptors, haem pigment concentration, and metmyoglobin percentages were also determined during storage duration on the minced raw meat. Lipid oxidation increased over time in cooked and raw meat (P<0.0005), but lower TBARS values were found in both cooked and minced meat from lambs fed vetch compared to those given concentrates (P=0.001; P=0.006, respectively). Higher a* values, lower b* values and lower hue angle values were observed in meat from H-fed animals as compared to meat from C-fed lambs (P=0.006; P=0.02; P=0.005, respectively). Metmyoglobin formation increased over time (P<0.0005), but the H diet resulted in lower metmyoglobin percentages than the C diet (P=0.006). Haem pigment concentration decreased over the 14days of storage (P<0.0005). We conclude that, under conditions that promote oxidative stress in meat, a herbage-based diet can improve the oxidative stability of meat compared to a concentrate-based diet.

Effect of different dietary tannin extracts on lamb growth performances and meat oxidative stability: comparison between mimosa, chestnut and tara.

Little information is available on the effects of different sources of tannins on ruminant product quality. Nowadays several tannin-rich extracts, produced from different plants, are available and contain tannins belonging to different chemical groups, but most of these have not been used so far as feed supplements. The present study aimed at comparing the effects of feeding three tannin extracts (one containing condensed tannins and two containing hydrolysable tannins) to lambs on growth performances and meat oxidative stability. Comisana male lambs were divided into four groups (n=9 each) and were fed for 75 days: a concentrate-based diet (CON), or CON supplemented with 4% tannin extracts from either mimosa ( MI; Acacia mearnsii, De Wild; condensed tannins), chestnut (CH; Castanea sativa, Mill; hydrolysable ellagitannins) or tara (TA; Cesalpinia spinosa, (Molina) Kuntze; hydrolysable gallotannins). Only CH reduced growth rate, final weight, carcass weight and feed intake (P0.05). The TA diet increased (P<0.001) the concentration of γ-tocopherol in muscle and tended to increase that of α-tocopherol (P=0.058). Oxidative stability of raw and cooked meat, or of meat homogenates incubated with pro-oxidants, was not affected by the extracts. These results, compared with those reported in the literature, highlight that some effects of tannins cannot be easily generalized, but may strictly depend on their specific characteristics and on conditions inherent to the basal diet and the metabolic status of the animals.

Caesarean section on request: are there loco-regional factors influencing maternal choice? An Italian experience.

We aimed to evaluate regional differences in women's motivations and in obstetricians' attitudes re 'caesarean section on request' between obstetricians practicing in Southern and Northern Italy. An anonymous questionnaire was sent to 70 randomly selected specialists practicing in the Veneto region and Sicily. Demographic characteristics, percentage of caesarean section, increase of caesarean section on demand, maternal motivations and the role played by anxiety, relatives and instrumental examinations were analysed. Moreover, obstetricians' opinion and their behaviour in fulfilling, or not, the maternal request were evaluated. Among the emotional reasons, fear of pain was more frequently reported in Sicily (p = 0.045), and previous negative experiences and gestational anxiety in the Veneto region (p = 0.009; p = 0.001). As regards instrumental examinations influencing maternal request, a significant difference was found for ultrasonography (28% in Sicily vs 60% in Veneto, p = 0.002). The husband's role was more frequently reported in the Veneto region (p = 0.006). Obstetricians of both regions noticed a rising rate of caesarean section on maternal request. The reasons for this upward trend are complex, vary from one region to another and are influenced by local socio-cultural and healthcare background.

Supplementation of Nigella sativa seeds to Barbarine lambs raised on low- or high-concentrate diets: Effects on meat fatty acid composition and oxidative stability.

Twenty-eight Barbarine male lambs were used to investigate the effect of dietary Nigella sativa seeds (NSS) on meat fatty acids and oxidative stability in two different feeding systems (high- or low-concentrate). Dietary treatments were planned to offer: 70% barley hay and 30% concentrate (LC); LC+12g/day of NSS (LCN); 30% barley hay and 70% concentrate (HC); HC+12g/day of NSS (HCN). NSS increased intramuscular fat only in the low-concentrate system (P=0.039); accordingly, the content of 14:0, c-9 14:1, t-9 18:1, t-11 18:1 and both individual and sum of odd and branched chain fatty acids were greater in LCN than LC meat. TBARS in raw meat increased from 0 to 3days of refrigerated storage regardless NSS supplementation. From 3 to 6days, TBARS further increased only in the meat from lambs not receiving NSS. At 6-days storage, TBARS were lower (P<0.05) in the meat of lambs receiving NSS compared to the meat of lambs not receiving NSS.

Intramuscular fatty acid composition of lambs given a tanniniferous diet with or without polyethylene glycol supplementation.

The aim of this trial was to investigate the effects that dietary tannins have on lamb intramuscular fatty acids. Twenty-seven lambs were divided into three homogeneous groups: control group, receiving commercial concentrate based on maize; tannin group, fed a diet based on carob pulp (45% as fed basis); PEG group, receiving the same diet as the latter with addition of 42g/kg of polyethylene glycol (PEG, a binding agent that eliminates the effects of condensed tannins). The duration of the trial was 45 d. Intramuscular fatty acids were measured in the longissimus dorsi muscle. The isomer cis-9 trans-11 of linoleic acid (conjugated linoleic acid or CLA) and linolenic acid were higher in the longissimus muscle fat from animals fed the control diet compared to the other groups (P<0.0005); these fatty acids were higher in the fat from animals fed the carob diet supplemented with PEG compared to those fed the same diet without PEG (P<0.05). trans-Vaccenic acid (C18:1 trans-11) was found at higher concentration in fat from control and PEG lambs compared to tannin lambs (P<0.01); the CLA/C18:1 trans-11 ratio was lower in lambs fed control and PEG diets than in tannin-fed animals (P<0.05).

Indoor fattening of lambs raised on pasture: 2. Influence of stall finishing duration on triglyceride and phospholipid fatty acids in the longissimus thoracis muscle.

Twenty-four male Ile-de-France lambs (six blocks of homologous lambs) were used to study the effect of four feeding systems on muscle triglyceride (TG) and phospholipid (PL) fatty acids (FA) from the longissimus thoracis (LT): raised and finished on cool season grasses (G), raised on the same grasses and stall-finished, indoors, on concentrates and hay, respectively, for 22 (GSS) and 41 days (GSL), and stall-feeding, indoors, on concentrate and hay during both growing and finishing periods (S). In TG, similar decreases (P<0.05) of proportions of linolenic acid were observed after changing from grass feeding to stall feeding (GSS and GSL), and a decrease (P<0.05) in proportions of conjugated C18:2 cis9, trans11 (CLA cis9, trans11) was obtained after a long period of concentrate feeding (GSL). In PL, C22:5 n-3 achieved a significantly (P<0.05) lower level in GSL lambs compared both G and S lambs. A similar non-significant tendency was observed in the case of the other very long chain n-3 polyunsaturated FA. The separate analysis of fatty acids of TG and PL from the LT muscle underlined that TG afforded a more significant lowering effect than PL on the overall ratio between C18:2 n-6 and C18:2 n-3 in muscle lipids and on the health potential of meat for the consumer. A PCA analysis combining FA composition of TG and PL, and growth performances of the lambs allowed an efficient discrimination between the four feeding systems.

Indoor fattening of lambs raised on pasture. Part 1: Influence of stall finishing duration on lipid classes and fatty acids in the longissimus thoracis muscle.

Forty male Ile-de-France lambs (10 blocks of 4 homologous lambs) were used to study the effects of four feeding systems on muscle fatty acids (FA): raising and finishing on cool-season grasses (G), raising on the same grasses and stall-finishing, indoors, on concentrates and hay, respectively, for 22 (GSS) or 41 days (GSL), and stall-feeding indoors on concentrates and hay during both growing and finishing periods (S). Twenty-four lambs only (6 blocks) were retained for comparison of growth performances, lipid content in the longissimus thoracis muscle (LT) and their FA composition according to treatment. The 16 other lambs (4 blocks) were removed from the comparison, due to a large spread in the growth of the lambs towards the end of the trial. No significant effects of treatment were seen on the rate of growth (221, 228, 243 and 245±SE 8.0g/d, respectively, for G, GSS, GSL and S groups), and the lipid contents of the LT (2.22, 2.16, 2.17 and 2.52±SE 0.11g/100g fresh tissue). Grazing, lowered n-6 PUFA (polyunsaturated fatty acids), and increased n-3 PUFA and C18:2 c9t11 (conjugated linoleic acid cis9, trans11) compared to concentrate feeding. The main effects of grazing were not removed by a short period of finish indoors on concentrate (GSS group), but C20:4 n-6 and C22:6 n-3 contents achieved the lowest contents in this group, with significant differences from the values observed for GSL and S groups (C20:4 n-6) or from the three other groups (C22:6 n-3). After a longer period of finish on concentrate (GSL group), C18:3 n-3 (linolenic acid), C18:2 c9t11 and long chain (LC) n-3 PUFA were brought to the levels observed in the S group. In terms of adequacy for human health, the C18:2 n-6/C18:3 n-3 ratios were favourably low in the four groups (2.6, 3.6, 4.9 and 5.2±SE 0.7, respectively, for G, GSS, GSL and S groups), the level observed in the case of G group being significantly lower than for the three other groups and the level observed for GSS group being significantly lower than for the GSL and S groups.

Vitamin E is the major contributor to the antioxidant capacity in lambs fed whole dried citrus pulp.

The aim of this study was to investigate the effect of dietary whole dried citrus pulp (DCP) on the antioxidant status of lamb tissues. In total, 17 lambs were divided into two groups and fed for 56 days: a barley-based concentrate diet (CON - eight animals), or a concentrate-based diet including 35% DCP to partially replace barley (CIT - nine animals). The CIT diet contained a double concentration of phenolic compounds than the CON diet (7.9 v. 4.0 g/kg dry matter (DM), respectively), but had no effect (P>0.05) on the overall antioxidant capacity of the hydrophilic fraction of blood plasma, liver and muscle. The CIT diet contained clearly more α-tocopherol than the CON diet (45.7 v. 10.3 mg/kg DM), which could explain the higher concentration of α-tocopherol in liver, plasma and muscle (P<0.05). The dietary treatment had no effect on the extent of lipid peroxidation, measured as thiobarbituric acid and reactive substances assay (TBARS values) in the faeces, small intestine, liver, plasma and muscle. Nevertheless, when muscle homogenates were incubated in the presence of Fe3+/ascorbate to induce lipid peroxidation, the muscle from lambs fed DCP displayed lower TBARS values (P<0.01), which negatively correlated with the concentration of α-tocopherol in muscle. These results showed that feeding whole DCP to ruminants increases the antioxidant status of muscle through an increase in the deposition of α-tocopherol.

Ruminant fat volatiles as affected by diet. A review.

Volatile compounds in meat have been widely studied for their favourable or undesirable effects on meat flavour, or for their potential use in tracing the animal feeding system. To date, the chemical mechanisms causing the appearance of volatile compounds in meat have been largely understood. Several variables are involved in the accumulation of volatiles in animal tissues and among them animal diet plays a key role. The purpose of the present review is to highlight the effects of different dietary regimes (concentrate, green grass and fat-enriched diets) on the appearance of fat volatile compounds in ruminant meat. Grain-based diets induce greater accumulations in meat of branched-chain fatty acids, some aldehydes, and lactones while meat fat from grazing animals contains high levels of phenols, terpenes, indoles and sulphur compounds. Fat-enriched diets exert their effect mainly on those volatiles which originate from polyunsaturated fatty acids. Cooking procedures have been considered for their contribution to fat volatiles in meat by reactions induced by high temperatures.

Lamb meat quality as affected by a natural or artificial milk feeding regime.

Fourteen Barbaresca lambs were divided into two groups of seven at 24h from birth and reared exclusively on natural milk (NR) or on artificial milk (AR). Lambs were slaughtered at 40 days of age. The NR group tended (P<0.10) to grow faster, thus resulting in a higher (P<0.10) carcass weight as compared to the AR group. AR meat was darker (P<0.05), leaner (P<0.001) and with a higher moisture (P<0.10) and ash (P<0.05) content than its counterpart. The proportion of polyunsaturated fatty acids was higher (P<0.01), while that of saturated lower (P<0.01) in meat from the AR group, resulting in a higher (P<0.01) polyunsaturated/saturated ratio. Linoleic acid content (P<0.001) and its n-6 series derivatives, except 9-12 trans C18:2 n-6 (P<0.001), increased more in the AR group meat than in the NR group. On the other hand, α-linolenic (P<0.001) and other n-3 series fatty acids were higher in meat from the NR group than in the AR group, leading to a lower (P<0.001) n-6/n-3 ratio. Furthermore, 9 cis 11 trans CLA was higher (P<0.001) in NR meat compared to AR meat. Finally, a milk-feeding regime exclusively based on artificial milk adversely affected the dietetic value of lamb meat compared to a natural rearing system, reducing the level of desirable fatty acids such as n-3 series and CLA.

Fatty acid composition of ruminal digesta and longissimus muscle from lambs fed silage mixtures including red clover, sainfoin, and timothy.

This work investigated the effects of feeding silage mixtures of a plant containing polyphenol oxidase (PPO; red clover [; RC]), a plant containing tannins (sainfoin [; SF]), and a grass species not containing these compounds (timothy [; T]) on ruminal and intramuscular (i.m.) fatty acids of lambs. Forty 4-mo-old castrated male Romane lambs, divided into 5 groups, received 1 of the following silages: 1) T (100%), 2) a binary mixture of timothy and tannin-containing sainfoin ( cv. Perly; 50:50 [T-SF]), 3) a binary mixture of timothy and PPO-containing red clover ( cv. Mervius; 50:50 [T-RC]), 4) a ternary mixture of timothy, sainfoin, and red clover containing both tannins and PPO (50:25:25, respectively [T-SF-RC]), and 5) a binary mixture of tannin-containing sainfoin and PPO-containing red clover (50:50 [SF-RC]). In the rumen digesta, the partial or total replacement of T with forage legumes was associated with greater concentrations of PUFA ( < 0.001) and 1esser concentrations of MUFA ( < 0.001). The inclusion of forage legumes in the silage favored the accumulation of 18:3 -3 ( < 0.001), with the greatest concentrations being observed in SF-RC. This latter diet also led to the greatest percentage of 18:2 -6 ( < 0.001). Forage legumes decreased the -11 18:1 to 30% of T in rumen digesta ( < 0.001). Forage legumes decreased the total concentration of branched-chain fatty acids in the rumen digesta (on average, -28%; < 0.001), this effect being less marked (-17%; = 0.014) in T-RC in comparison with T. The dietary treatment tended to affect the proportion of MUFA ( = 0.081) and of PUFA ( = 0.079) in the i.m. fat of the LM, respectively, at the highest and lowest numerical value in the T group. The sum of -3 fatty acids was less in the T and T-SF groups compared with the mixture of legumes without T (SF-RC; < 0.001 and < 0.008, respectively). The latter group had also a lesser -6-to--3 ratio than the T-SF group ( = 0.01). -11 18:1 was greater ( < 0.03) in lambs given T as the sole silage in comparison with lambs given T-RC, T-SF-RC, and SF-RC. Rumenic acid (-9 -11 CLA) was detected at a greater percentage in the LM from the animals fed the T silage compared with animals fed the T-SF-RC treatment ( = 0.004). Contrarily, -9 -12 -15 18:3 was found at a greater concentration in the muscle from lambs in the SF-RC treatment compared with lambs in the other treatments ( < 0.001). Furthermore, the T-RC group showed a greater proportion of α-linolenic acid than the T group ( = 0.03). In conclusion, the effects of the 2 active compounds (PPO and tannins) appear to be similar and additive. Moreover, a silage composed of a mixture of RC and SF is an excellent forage for growing lambs in terms of i.m. fatty acid composition.

Effect of including carob pulp in the diet of fattening pigs on the fatty acid composition and oxidative stability of pork.

The effect of feeding pigs with carob pulp on meat quality was investigated. Nine pigs were finished on a conventional concentrate-based diet (control), while two groups received a diet comprising of the same ingredients with the inclusion of 8% or 15% carob pulp (Carob 8% and Carob 15%, respectively). Feeding carob-containing diets reduced the concentration of saturated fatty acids in the muscle, increased the concentration of monounsaturated fatty acids in meat (P < 0.01) and of n-3 polyunsaturated fatty acids (PUFAs) and reduced the n-6/n-3 PUFA ratio (P < 0.001). The meat underwent slow oxidative deterioration over 9 days of storage. However, the Carob 15% treatment increased meat susceptibility to lipid oxidation across storage (P = 0.03), while the dietary treatment did not affect meat colour stability. In conclusion, feeding pigs with carob pulp could represent a strategy,in the Mediterranean areas, to naturally improve meat nutritional value and to promote the exploitation of this local feed resource.

Fatty acid metabolism in lambs fed citrus pulp.

In the present study, we have hypothesized that replacing barley with high proportions of dried citrus pulp in a concentrate-based diet for lambs could increase the intake of unsaturated fatty acids and could reduce the rate of the ruminal biohydrogenation of PUFA, with a consequent improvement of the intramuscular fatty acid composition. To test this hypothesis, 26 Comisana lambs were divided into 3 groups and for 56 d were fed a barley-based concentrate diet (CON; 8 lambs) or 2 diets in which barley was replaced with 24% (CIT24; 9 lambs) or 35% (CIT35; 9 lambs) dried citrus pulp. An overall improvement of the fatty acid composition of LM from lambs fed citrus pulp-containing diets was found. The PUFA/SFA ratio was lower (P < 0.05) in the LM from lambs in the CON group compared with both the CIT24 and CIT35 groups. The thrombogenic index was lower (P < 0.05) in meat from lambs fed the CIT35 diet compared with those fed the CON diet. The CIT35 diet increased the proportion of C20:5 n-3 in the LM (P < 0.05), whereas the CIT24 diet enhanced that of C22:6 -3 (P < 0.05) compared with the CON diet. Some of these results might be explained considering that feeding the CIT24 and CIT35 diets increased the intake of total fatty acids (P < 0.05) and of C18:3 n-3 (P < 0.01) compared with feeding the CON treatment. On the other hand, phenolic compounds present in citrus pulp could have inhibited the ruminal biohydrogenation of PUFA. This is supported by the fact that regardless of the level of inclusion in the diet, citrus pulp increased the proportion of rumenic acid (P < 0.001) in LM compared with the CON diet. The plasma from lambs fed both CIT24 and CIT35 diets had a greater percentage of vaccenic acid (VA; < 0.001) compared with that from lambs fed the CON diet, and the CIT35 diet increased the proportion of rumenic acid in plasma compared with the CON treatment (P < 0.05). In the ruminal fluid, stearic acid (SA) tended to decrease, and the sum of CLA tended to increase (P = 0.09) with increasing level of citrus pulp in the diets. Furthermore, the SA/(SA + VA) ratio tended to be lower (P = 0.10) in the ruminal fluid from lambs fed the CIT35 diet compared with that of the CON group. In conclusion, our results support the hypothesis that replacing barley with citrus pulp in the diet of growing lambs improves intramuscular fatty acid composition and underline the need for specific studies to clarify the mechanisms by which feeding citrus pulp affects the fatty acid metabolism in ruminants.

Volatiles in raw and cooked meat from lambs fed olive cake and linseed.

This study was conducted to determine the effects of feeding olive cake and linseed to lambs on the volatile organic compounds (VOCs) in raw and cooked meat. Four groups of eight male Appenninica lambs each were fed: conventional cereal-based concentrates (diet C), concentrates containing 20% on a dry matter (DM) basis of rolled linseed (diet L), concentrates containing 35% DM of stoned olive cake (diet OC), or concentrates containing both rolled linseed (10% DM) and stoned olive cake (17% DM; diet OCL). The longissimus dorsi muscle of each lamb was sampled at slaughter and was subjected to VOC profiling through the use of SPME-GC-MS. In the raw meat, the concentration of 3-methylpentanoic acid was higher in treatment C as compared with treatments L, OC and OCL (P<0.01). Moreover the level of nonanoic acid was greater in treatments C and OC than in treatment L (P<0.05). With respect to alcohols, in raw meat the amount of 2-phenoxyethanol in treatment OCL was lower than in treatments C (P<0.01) and OC (P<0.05), while in cooked meat the amount of 1-pentanol was higher in treatment C than in treatment OC (P<0.05). Apart from these compounds, none of the lipid oxidation-derived volatiles was significantly affected by the dietary treatment. Therefore, the results suggest that the replacement of cereal concentrates with linseed and/or olive cake did not cause appreciable changes in the production of volatile organic compounds in lamb meat.

Persistence of carotenoid pigments in the blood of concentrate-finished grazing sheep: its significance for the traceability of grass-feeding.

Carotenoid pigments are good biomarkers of grass feeding in sheep. However, grazing lambs are often stall-finished because of grass shortage. We investigated the nature of the carotenoids present in sheep blood and their persistence in this tissue. Four treatments were compared: 1) feeding a concentrate-based diet (n = 10 lambs), 2) grazing followed by a long stall-finishing period (n = 10), 3) grazing followed by a short stall-finishing period (n = 10), and 4) grazing to slaughter weight (n = 10). The concentrate supply was regulated to have similar average daily gain for all treatments. The 40 lambs were allocated to either the grazing or the stall treatments on the basis of their birth date, birth weight, and body weight. The 30 grazing lambs were further allocated to long-stall, short-stall, or grass treatment on the basis of their body weight and plasma carotenoid content. Plasma content of total carotenoids was measured by spectrophotometry during the grazing and the stall periods for all lambs and at slaughter weight for the eight heaviest lambs of each treatment. Analysis of the nature and the concentration of individual carotenoids was performed by HPLC on pasture and stall diets and on blood of grazing lambs. The carotenoid content of the stall diet was 2 to 3% that of the pasture diet. Lutein, zeaxanthin, and beta-carotene accounted for 43 to 58%, 3 to 17%, and 0 to 7% of total plasma carotenoids in grazing lambs, respectively. Two unknown polar carotenoids, expressed in lutein equivalent, accounted for 10 to 22% and 0 to 9% of total carotenoids. Plasma carotenoid content during the grazing and the finishing periods varied among animals (P < 0.001). At slaughter weight, plasma carotenoid content was higher for grass-fed than for stall-fed, long-stall finished, or short-stall finished lambs (P < 0.001), and reliably distinguished grass-fed lambs from all the others. Plasma carotenoid content decreased exponentially with the interval from starting on the stall diet (P < 0.005). The deceleration parameter of the model increased linearly with lamb average daily gain during the stall-finishing period, suggesting that the turnover of carotenoids in the blood may depend on the level of intake of the stall-finishing diet. After 4 to 13 d on the stall diet, depending on the initial plasma carotenoid concentration, plasma carotenoid concentration of previously grazed, stall-finished lambs fell to the values of lambs fed a concentrate diet without grazing. Such a low persistence is of interest for discriminating grazing lambs from stall-finished grazing lambs.